Q. In the circuit shown, the reading of ammeter when switch $S$ is open and when switch $S$ is closed respectively are
A) $3\ A$ and $4\ A$
B) $4\ A$ and $5\ A$
C) $5\ A$ and $6\ A$
D) $6\ A$ and $7\ A$
Explanation
(b) When switch $S$ is open total current trough ammeter
$i = \frac{20}{(3 + 2)} = 4A$
When switch is closed $i = \frac{20}{3 + (2||2)} = 5A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.